Mail server host name in greeting

I have recently done a dnsstuff.com test on my ispconfig server, and it reports everything back that I expected, except for one warning... It's reporting...
"Mail server host name in greeting"
My domain is otherdata.com, otherdatanetworks.com

I could have swore that the last time I ran dns tests, I did not get this warning. Is it possible for something to have changed for postfix on my server?

I have this same thing happening; how does this work when hosting more than one domain?

For example, right now I have 123.com and abc.com.

If I run a check on abc.com, it might come back saying "WARNING: One or more of your mailservers is claiming to be a host other than what it really is...mail.abc.com claims to be non-existent host GW.123.com: 220 GW.123.com ESMTP Postfix (Ubuntu)"

/etc/mailname says it is GW.123.com.

Is the problem that it is "claiming" to be GW.123.com or is it that GW.123.com doesn't have a DNS entry? (Or both??)

The name your server uses for the HELO should preferably be an existing hostname (in DNS that is), with the reverse DNS for that IP being the same name. However, although it has become more customary to check for this relation and refuse mail if:
- you don't send a fully qualified name (missing dots)
- you send their own hostname(s) or their IP
- you send "localhost"
and of course:
- if your greeting doesn't match DNS and/or reverse IP.

A setup-checker (as you probably used) can detect all of this, but it doesn't really matter. Most sites hapily accept all kinds of BS, as http://www.faqs.org/rfcs/rfc2505.html makes these checks optional (MAY) or doesn't mention them. Rfc2505 mostly caused open relays to vanish. It's outdated, but there's no new standard, let alone a good solution.

Bottomline: try go get /etc/mailname in line with a forward DNS name and preferably with your reverse DNS too. If not, at least change mailname to your current DNS name.

Tebokkel, are you saying the name doesn't really matter, so long as it is a valid name that exists in DNS? So for example, if i am sending from abc.com it is OK if it identifies itself as GW.123.com so long as GW.123.com resolves to the correct IP?

So based on the input, maybe I should just change /etc/mailname to something that resolves or create a record for GW.123.com?

Tebokkel, are you saying the name doesn't really matter, so long as it is a valid name that exists in DNS? So for example, if i am sending from abc.com it is OK if it identifies itself as GW.123.com so long as GW.123.com resolves to the correct IP?

Click to expand...

yes.

So based on the input, maybe I should just change /etc/mailname to something that resolves or create a record for GW.123.com?

my current mailname is h1870666.stratoserver.net and reverse pointers are on for this.
I just double checked the perfect debian squeeze server setup with apache2 for ispcfg3 and can't find anything about the mailname so what would I need to change it to so it works for all hosted domains?

Ok, but since I mentioned the server is using ispcfg and hosting multiple domains and email domains, what would I change the hostname to? which domain? So I guess this is the way it is with hosting multiple email domains